Wire guides are used in a variety of medical procedures. For example, wire guides are typically used to gain access into a blood vessel, duct, or organ during a minimally invasive medical procedure. Once the wire guide has been introduced and positioned, the wire guide may then be used to facilitate the subsequent introduction or placement of catheters and other medical devices. This basic procedure is commonly known as the Seldinger technique, and was first popularized during the late 1950s and 1960s.
Conventional wire guides must have sufficient flexibility and torque control for navigation through tortuous vessels and ducts. At the same time, the wire guide must have a certain amount of rigidity to pass through lesions, straighten extremely tortuous vessels, and support medical catheter devices that are subsequently introduced over the wire guide. Wire guides are therefore subject to potentially conflicting requirements. For example, more flexible, smaller diameter wire guides are preferable for navigation of extremely tortuous vessels and ducts. However, in some situations the tip of the wire guide may prolapse away from the site to which access is trying to be gained, or when encountering obstructions within the vessel or duct. On the other hand, stiffer, larger diameter wire guides generally do not have sufficient flexibility to navigate extremely tortuous vessels or ducts. Larger diameter wire guides may also be too large to be used to introduce smaller catheter devices having small wire guide lumens. In addition, certain portions of the vessel or duct may require a stiffer, larger diameter wire guide, whereas other portions of the vessel or duct may require a more flexible, smaller diameter wire guide. As a consequence, the user may need to introduce multiple wire guides having different diameters and properties.
In an exemplary medical procedure, the user begins with a larger diameter, stiffer wire guide to gain access through the larger, less tortuous vessel or duct. As the vessel or duct becomes smaller and more tortuous, the user may need to replace the larger wire guide with a more flexible, smaller diameter wire guide to gain access therethrough. The wire guide exchange may be accomplished by passing a catheter over the first wire guide until the distal end of the catheter is near the distal end of the wire guide. The wire guide is then withdrawn and removed from the catheter. Once the first wire guide is removed, the catheter can then be utilized to introduce and advance the second wire guide through the wire guide lumen of the catheter. The catheter provides the necessary support for the second wire guide as it is being advanced there through. The second wire guide can then be extended beyond the distal end of the catheter to gain access to the next section of the vessel or duct. If an obstruction or tortuous pathway is encountered that can not be passed by the second wire guide, then the second wire guide may need to be replaced with a third wire guide.
The need to exchange wire guides during the medical procedure adds to the complexity and duration of the procedure. In addition, exchanging one wire guide for another increases the likelihood of contamination to the patient and to those performing the medical procedure. Accordingly, there is a need to provide a wire guide that can be altered during the medical procedure to reduce or increase its stiffness, cross-sectional shape or diameter.
In another exemplary procedure, the user may need to introduce a second wire guide along side the first wire guide. In particular, the user may need to simultaneously gain and maintain access to each leg of a bifurcated duct. For example, the user may need to introduce a first wire guide into the biliary duct and a second wire guide into the pancreatic duct. In such a procedure, the user will introduce the first wire guide into the biliary duct using the conventional manner. The user will then attempt to introduce the second wire guide into the pancreatic duct by first threading it along side of the first wire guide and into the biliary duct, and then subsequently into the pancreatic duct. The procedure is time consuming and difficult, particularly since the biliary duct may be partially obstructed by the presence of the first wire guide. Accordingly, there is a need to provide a wire guide that can be separated during the medical procedure into two or more separate wire guide members, wherein each of the wire guide members may be used to gain access to a different vessel or duct.